Websocket support in cdn.skypack.dev asset?

How do I change the import to get the turbo with support for web sockets?

I am importing turbo like so:

  <script type="module">
    import hotwiredTurbo from 'https://cdn.skypack.dev/@hotwired/turbo';

But when I search for TurboCableStreamSourceElement in the CDN’s Javascript, I get no hits … which makes sense, as the class is defined in turbo-rails, and not in the turbo repo. How can I get the turbo.js version that is used in the chat demo, which includes the web socket support?